*2.3.1 Dry farming and terracing*

These are commonly practiced in the western highlands of Cameroon. Terracing is practice across steep-slop banks on the western highlands with main crops cultivated such as plantains, yams, and potatoes. Dry farming system is practiced along the few fertile gentle slopes and in localities of undulating reliefs [3].

### *2.3.2 Intercropping and mixed cropping*

These are practiced mainly by smallholder farmers. The practices differ from one agro-ecological zone to another but many characteristics of these practices are the same nationwide. Intercropping/mixed farming is mostly carried out on small farm sizes, generally those <2 hectares. Most of the intercrop mixes contain one leguminous crop. Crops intercrops are selected based on their importance for household consumption and market. While there are cases where food crops are intercropped with cash crops, the practice is predominantly carried out by food crop farmers [4]. Some of the farmers grow more than two crops on the same land during one growing season, especially those cultivating on a land size <1 hectares [3]. Some of such farms also have one or more livestock.

#### *2.3.3 Crop rotation*

This is the practice of planting different crops sequentially on the same land to reduce the spread and rapid attack of crops by pests and diseases. The crops also differ from one agro-ecological zone to another.

#### *2.3.4 Mono cropping*

This is commonly practiced by large scale farmers >5 hectares. This cropping system is mostly industrial agricultural institutes such as CDC, PAMOL,


#### **Table 1.**

*Agro-ecological of Cameroon characteristics, geographical features, rainfall patterns and major crops cultivated and animal species reared (source: authors compilation).*

SOCAPALM, Tole tea etc. where they cultivate crops like palms, banana, tea, rubber etc.

#### **2.4 Main constraints in the agricultural sector**

Like most developing countries, the agricultural sector in the country faces lots of constraints; (i) poor farm-to-market roads, (ii) insufficient access to finance, (iii) most are small farms still using rudimentary tools, (iv) most of the smallholder farmers have not been trained on good agricultural practices, (v) insufficient links to market and market information, (vi) insufficient and low standard transformation/processing of commodities, (vii) pests and diseases are a major constraint, (viii) most of the smallholder farmers misusing agrochemicals.

#### *Insecticide Use and Application in Cameroon DOI: http://dx.doi.org/10.5772/intechopen.102634*

Biotic constraints (pests and pathogens) are seriously hindering the crop production, resulting to pre-harvest losses, post-harvest losses and lower yields. Arthropod pests especially insects are the most common and serious group causing damage to crops. Most damaging insect Orders are Coleoptera, Lepidoptera, Hemiptera, and Diptera. Most mentioned group of disease-causing agents are fungi and viruses. Severity of the pests and diseases varies with the crop and crops hardest hit by diseases are cocoa, tomatoes, banana/plantain, onions, sorghum, maize, pineapple, cucumbers, pepper and water melons while those hardest hit by pests are cocoa, tomatoes, maize, groundnuts, bananas/plantains, sorghum, millet, cotton, pineapple, coffee and cucumbers.

The different agro-ecological zones are faced with biotic and abiotic constraints that affect the agricultural productivity. Pests are mainly from the arthropod, vertebrate, mollusk, weeds and nematode groups of living things. Disease-causing pathogens are mainly fungi, viruses and bacteria. For cocoa, black pod; capsids; rodents and primates reported as the main pests/diseases. Corm borer weevils, mealy bugs, aphids, snails, black sigatoka, banana bunchy top disease and Banana streak virus for bananas/plantains; blight, fruit flies, white flies, aphids and mole crickets for tomatoes, peppers, and African nightshade; fall army worm, stem borers, snails, rust and maize weevil for maize; boll worm for cotton; bruchids for cowpea; thrips and mildew for onions, leaf miners for oil palm, grasshoppers, caterpillars, aphids and whiteflies also attack lots of traditional African vegetables.
